Lawn mower grinder



June 14, 1949. I c THOMPSON 2,473,313

LAWN MOWER GRINDER Filed Sept. 10, 1947 3 Sheets-Sheet 1 Inventor A/berf C. Thompson June 14, 1949. A. c. THOMPSON 2,473,313

' LAWN MOWER GRINDER Filed Sept. 10, 1947 I 5 Sheets-Sheet 2 Inventor Albert 6. Thompson June 14, 1949. A. c. THOMPSON LAWN MOWER GRINDER 3 Sheets-Sheet 3 Filed Sept. 10, 1947 m m V m w E 9% v9 P m5 @vn I NE o wk H x mv m3 v I N H n W v9 E ww vQ vw @Q 9 mm Q8 I, g SiiiaiitiiMmW wm Q N\\ NS D I m9 E g Q Albert 0. Thompson a Attorneys Patented June 14, 1949 UNITED STAT E-S PAT ENT F Fl CE 2373313 LAWN MOWER GRINDER Albert Thompson, Fountain city, Tenn. Application September 10, 1947, Serial No. 17:3,25'8

(CLSI- lt) 1 Claim. 1 V This invention appertainis to novel and usefdl improvements in machine tools, particularly that class of machine tool which is adapted to perform special jobs. v

An object of this invention is to efficaciously and conveniently grind the blades of a lawn mower without removing the said blades rrcm the housing normally associated therewith. Another object of this invention is to provide means for carryin out the above mentioned function. I I A further object of this invention is to provide a. novel and improved support for retaining a lawn mower in a fixed, desired position.

Another purpose of this invention is to ,provide means for grinding the blades of the said lawn mower and for simultaneously grinding and rotating conventional arcuate blades in order to provide a surface normal to the said abrading means at all positions during the cycle of operation. I

Another purpose of this invention is to provide improved means for actuating the abradin'g means in planes mutually perpendicular.

Another purpose of this invention is to provide an improved method of sharpening lawn mowers. Another purlopse of this invention is to retain a lawn mower in a fixed position while grinding the blades thereof by moving an'abrading means in a single plane against thesa'id mower blades and simultaneously rotating "the said blades.

Ancillary objects and features of novelty will become apparent to those skilled in the art, in following the description of the preferred form of the present invention, illustrated the accompanying drawings, wherein:

Figure 1 is an elevational side view of the preferred form of the present invention;

Figure 2 is a side view of the invention shown in Figure 1, taken from the opposite side thereof; Figure 3 is a transverse sectional view of the invention shown in Figure 1 and taken substanmany on the line 3- 3 thereof and in the di rec tion of the arrows;

Figure 4 is a fragmentary sectional view of the invention shown in Figure 1 and taken substantially in the direction of the arrows indicated at 4-4;

Figure 5 is a longitudinal sectional view of the abrading means including the retaining means for the said abra'ding means;

Figure 6 is a sectional view of the invention shown in Figure 1 and taken substantially on the line B-B thereof and in the direction of the arrows; and

Figure '7 is "a sectional view of the abradin'g means shanhousin'g'retammg means.

Referring now'in detail to the illustrated preferred embodiment of the presentinvention, like iie'ference characters are used throughout to indicatesimilar elements thereof,

invention has been conceived and developed I'i'dr the purpose of more efficac'iously and conveniently sharpening lawn mower blades without the necessity of removing the said blades from the other appurtenances contiguous to lawn mowers. It is within the purview of the present invention to sharpen the lawn mower blades by .ietaining the actual lawn mower in a fitted position, moving an l-abrading means over the said blades within the lawn mower in .a single plane, and rotating the said blade to provide this mutually perpendicular lconstruction between the edge of the blades and the abracling means.

The utility of the present invention renders sharpening conventional lawn mower blades very simple and easy; it only need be necessary to adjust the mechanism and slide the abrading means in a single plane, the lawn mower blades rotating the proper amount automatically. v

A base, generally indicated at I0, is provided and is preferably composed of a pair of leg :members l2 and M, respectively, having a cross member extending therebetween for support purposes. The base extends through the utility of plates 18 and 20, respectively, which are detachably secured to the leg members 12 and Id. The rail 22 is secured to the said extensions or plates I8 and 20 and has a relatively sharp top edge 24 longitudinally thereof. A carriage is slidably received on the -said rail 22 and is provided with a detent complemental to the sharpened portion 24 for engagement with said sharpened portion. The said carriage is composed of a plurality of members '26 and 28, connected with cross members. A table extends from the said carriage and a motor :32 is secured to the said table. 7 e v Means io'r slidably actuating'the said carriage is provided. This actuating means may be seen best in Figure 2 wherein there is disclosed an arm 34 secured to the said base having a wheel 36 journaled therein. A pulley 38 is operatively associated with the said wheel 36 and a belt Ml extends therearound. This belt also extends around a second large wheel or pulley 42 which is also journaled in the said base. Operatively associated with the pulley 42 is a gear 46 having a chain 48 extending. there'around; Adjustably positioned at the opposite end of the said frame 3 I is another idler pulley or gear 50 about which extends the said chain 48.

Going now to Figure 3, it will be noted that the said chain 46 is rigidly secured to the said carriage through the medium of a, pin 52 and extends over a second idler pulley 54 journaled in the said rail 22. It may be appreciated that upon rotation of the wheel 36, the carriage will be slid longitudinally of the said rail 22.

A frame is adjustably received in the said carriage for the purpose of supporting an abrading means. This frame is composed of a pair of rods 56 and 58, respectively, which are slidably received in suitable tracks 60 forming a part of the said carriage. Suitable cross members are secured between the said frame for the obvious purpose of adding rigidity thereto. A bracket 62 extends from the said last-mentioned cross member means and forms a bearing for a shaft 66. This shaft 66 has collars 68 and I0 secured in spaced relation thereon. Each of the said collars is positioned on an opposite side of the said brackets 62, thereby preventing axial movement of the said shaft 66, relative to the frame. A perch I2 extends from the carriage and is internally threaded, complemental to the threads on the shaft 66. A suitable handle I4 may be detachably secured to a terminal portion of the said shaft 66 for actuation thereof. It is obvious that upon rotation of the shaft in a selected direction, the frame will be raised and lowered selectively.

The terminal portions of the said carriage. members 56 and 58 are apertured for the purpose of receiving a hollow shaft I6 therein. This hollow shaft has internal anti-friction bearings I8 at opposite ends thereof for the purpose of journaling a. work shaft 80 therein. For this construction, reference is made primarily to Figure 5. It will also be noted that a pulley 82 is secured to one end of said shaft 80 while abrading means 84 is detachably associated with a reduced portion 86 of the said shaft 80.

The said pulley 82 has a belt 88 extending therearound, which belt also extends around a pulley 90 detachably associated with the armature shaft of the motor 32.

It is quite evident that upon lifting and lowering of the shaft 80, the belt 88 will be pulled therewith. Accordingly, the motor 32, being positioned on the plate 30, is so arranged as to move pivotally therewith. For this construction, reference is made primarily to Figures 2 and 3. It will be seen that the table 30 is provided with eye members 92, as also the carriage. A pivot pin 94 then extends through all of the said eye members, thereby rendering the motor pivotal about the pivot pin 94 as an axis.

It will be here noted that the idler gear 50 is adjustable relative to the longitudinal axis of the rail 22. Going to Figure 6, it will be seen that an insert 96 is slidably received within an extension 98 provided on the base I0. Friction means I00, preferably a screw, is received in the said slidable means 96 and engageable with the stub shaft I02 on which the said idler pulley 50 is iournaled.

Means for supporting a lawn mower is provided. This means consists of a pair of supports I04 and I66, respectively, which are operatively associated with the said base. A pair of identical lawn mower engaging ends are provided on each of the said supports I04 and I05, respectively. Going to Figure 3, it will be seen that a link I08 is pivoted centrally thereof to the said .4 support I04. An upper screw H0 is adjustably received in the said link I08 and has a cup-like housing at the terminal portion thereof. This housing is for the purpose of engaging the shaft means of a lawn mower. The lower screw II2 has a conical point thereon for the purpose of engaging another selected element of a conventional lawn mower in the retention of the lawn mower between the supports I04 and I06. Now, a perch I I4 is secured to the said support I04 and a screw threaded shaft II8 extends therethrough. This shaft also extends through the member connecting the upper portion of the link I08 thereto. By this medium, the angle of inclination of the link I08 may be adjusted. Means for resiliently biasing said link in a selected position is also provided. This means is preferably a spring I20 extending from the lower portion of the said link to a suitable eye member I22 integral with the support I04.

It is noted that the supports I04 and I06 are pivoted at I26 to the said base. A rod I28 having an internally threaded bearing I30 at the terminal portion thereof is provided. Extending into the said bearing I30 is an externally threaded shaft I 32 which also extends through a suitable bearing I34 provided in the said support I04. Suitable handle means I36 is associated with the terminal portion of the said threaded shaft I32 for the obvious purpose of applying torque to the said shaft. By adjustment of this threaded shaft I32, the entire assemblage for retaining the lawn mower may be pivotally adjusted.

After the lawn mower is rigidly attached on the pertinent securing means, the sharpening operation begins. Going now to Figure 4, it will be noted that a plate I36 is attached adjacent the hollow shaft I6 and has a lip I38 associated therewith. This lip engages the blades I40 of the said lawn mower, thereby turning the said blades about their normal shaft for supplying fresh surface or edge of the lawn mower blades in a perpendicular position relative to the grindstone or abrading means 84.

In this manner and by the above described structure, lawn mower blades may be easily, conveniently and economically sharpened.

Due to the extreme simplicity of operation of this invention, a further description thereof is deemed unnecessary. However, it is apparent that various departures may be made from this invention without departing from the spirit thereof. Accordingly, limitation is sought only in accordance with the scope of.the following claims.

Having described the invention, what is claimed as new is:

A lawn mower sharpener comprising a base, a rail secured to said base and a carriage slidably disposed on said rail, a frame vertically movable on said carriage, and threaded means reacting on said carriage for retaining said frame in preselected vertical positions, a shaft mounted for rotation on said frame adapted to support an abrading means, a hand wheel mounted on said base, and means d'rivingly connecting said hand wheel and said carriage to slidably actuate said carriage, a motor, a table pivoted to said carriage supporting said motor. and means drivingly connecting said shaft and said motor, a pair of supports mounted on said base, links pivoted to said supports, upper screws mounted on said links adapted to engage the shaft of a lawn mower, and lower screws carried by said links to engage a said supports for adjusting the angle of inclination of said links.

ALBERT C. THOMPSON.

REFERENCES CITED The following references are of record in the file of this patent:

Number STATES PATENTS Name Date Utterback Jan. 16, 1940 Shelburne Apr. 14, 1942 Maynard et a1 Mar. 30, 1943 

